Remote control system, remote control apparatus, remote control method, program for implementing the method, and electronic appartus

ABSTRACT

A remote control system which can reliably provide desired control while saving power. A remote control apparatus is capable of carrying out two-way wireless communication with an apparatus to be controlled. A control signal corresponding to a key switch for remote control is repeatedly transmitted while the key switch is being operated. Repeated transmission of the control signal is inhibited in accordance with reception of a predetermined signal from the apparatus to be controlled.

This application is a division of application Ser. No. 10/771,751, filedFeb. 3, 2004 (currently pending), which is incorporated herein in itsentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a remote control system, a remotecontrol apparatus, and a remote control method, which carry out remotecontrol (remote operation) of an electronic apparatus by means of e.g.infrared light, as well as to a program for implementing the method andan electronic apparatus which is remotely controlled. In particular, thepresent invention relates to a remote control system, a remote controlapparatus, and a remote control method, which carry out remote controlof an electronic apparatus by sequentially transmitting control signalsfor providing predetermined control, as well as to a program forimplementing the method and an electronic apparatus which is remotelycontrolled.

2. Description of the Related Art

Conventionally, in a remote control apparatus (hereinafter referred toas “the remote controller”) which remotely controls an electronicapparatus such as a television set or a vide camera by means of infraredlight, in the case where, for example, the volume of a television set orthe direction of a video camera which captures an image are controlled,the operator continuously depress a control key for controlling thevolume or the direction to sequentially transmit control signals to theelectronic apparatus so as to sequentially change the volume or thedirection, and stops depressing the control key when a desired volume ordirection is obtained.

In response to the depression of the control key, the remote controllertransmits a light signal (control signal) with a data format in FIG. 21Aonce. Specifically, FIG. 21A is a view showing a code system in theformat of the light signal; reference numeral 301 denotes a leader code.Reference numeral 302 denotes a custom code for identifying e.g. themanufacturer of an electronic apparatus or the model of a set for whichthe remote controller is used. Reference numeral 303 denotes a paritycode; 304, a data code; and 305, an END code which is called a trailer.

FIG. 21B is a view showing a signal waveform applied to a light emittingdiode (LED), and for example, the leader code 301 is comprised of asignal present section with a duration of 8T (“T” means the basic timeunit of a code), and a signal absent section with a duration of 4T.

On the other hand, if the control key is continuously depressed, theremote controller continuously transmits a repeat code 306 with a formatin FIG. 21C at predetermined time intervals of about 100 ms, forexample. FIG. 21D is a view showing the signal waveform of the repeatcode 306, which is applied to the light emitting diode (LED).

The above-mentioned formats have been disclosed in “Transistor Gijyutsu,November 1996 issue” (CQ Publishing Co., LTD.), and detailed descriptionis therefore omitted.

Also, Japanese Laid-Open Patent Publication No. H08-163531 has discloseda technique for controlling a VTR via a CATV using a remote controllertherefor in a system which controls the VTR by means of an infraredcontrol unit attached to the CATV.

This publication discloses an arrangement that a control signal istransmitted via a remote controller, (light), CATV, (cable), theinfrared control unit, (light), and the VTR in this order, and toprevent abnormal reception due to collision of light from the remotecontroller and light from the infrared control unit, the publicationfurther discloses a technique according to which a control signal istransmitted only immediately after a key of the remote controller isdepressed, and immediately upon receiving the control signal, theinfrared control unit transmits a control signal to the VTR, and atechnique according to which a control signal is transmitted immediatelyafter a key of the remote controller is depressed, and a control signalis again transmitted when the key ceases to be depressed, and while theremote controller transmits no control signal, the infrared control unittransmits a control signal to the VTR.

The above-mentioned repeat code 306, however, is only indicative of “thesame as before”, and therefore, in the case where an electronicapparatus as an apparatus to be controlled fails to receive the initialdata (leader code 301), what kind of instructed operation should beexecuted cannot be recognized, and thereafter, even if the repeat code306 is transmitted, the electronic apparatus only has to make the repeatcode 306 through.

Further, according to the techniques disclosed in Japanese Laid-OpenPatent Publication No. H08-163531, a signal is transmitted from theremote controller only once or twice, and hence the CATV can fail toreceive an infrared light signal with a high possibility, and the sameproblem arises as in the case where the repeat code 306 is used.

In either case, the operator of the remote controller misbelieves thatthe remote controller or the apparatus to be controlled has failed sincethe apparatus to be controlled does not operate in response to thedepression of a key, or misbelieves that an intended key of the remotecontroller has not yet been turned on, and therefore continuouslydepresses the key with an excessive force, and therefore the remotercontroller is not easy to use.

There has been known a remote controller which repeatedly transmits thesame control signal during the depression of a key, and this remotecontroller can solve the above described problems since the same controlsignal as the previous one is repeatedly transmitted even if anapparatus to be controlled has failed to receive the first signal.

However, in the case of a key such as a channel switch key for a TV setor a video signal input switch key other than a key used for e.g. volumecontrol which requires an instruction for continuous operation, acontrol signal is continuously transmitted although the control signaldoes not have to be repeatedly transmitted even if the key iscontinuously depressed (this also applies to the case where the repeatcode 306 is transmitted), and this wastes a battery for the remotecontroller.

Here, in the case where the key is slowly depressed once, the key isusually depressed for several 100 ms, but the transmission of one signalis completed in several 10 ms. Therefore, when the key is depressed, acontrol signal is unconsciously transmitted about four or five times.Thus, even if the operator tries to prevent the waste of battery for theremote controller by consciously decreasing the period of time for whichthe key is depressed, there is a limit.

To address this problem, it can be envisaged that a control signal istransmitted only once even if a key which does not require aninstruction for continued operation is continuously depressed.

In this case, however, since one signal is transmitted for only a shortperiod of time, i.e. about several 10 ms as described above, theapparatus to be controlled can fail to receive a control signal with ahigh possibility in the environment where there are a large amount offluorescent light of a fluorescent lamp or other disturbance light. Inthis case, as described above, the operator of the remote controllermisbelieves that the remote controller or the apparatus to be controlledhas failed since the apparatus to be controlled does not operate inresponse to the depression of the key, or misbelieves that an intendedkey switch for the remote controller has not yet been turned on, andtherefore, should continuously depress the key with an excessive force.Therefore, the remote controller is not easy to use.

Further, in the case of the remote controller which repeatedly transmitsthe same control signal during the depression of a key, if the receptionof a control signal is interrupted by an obstacle or the like during thedepression of a key, and then the obstacle or the like is removed toreceive the next control signal, the apparatus to be controlleddetermines that the key has been released once and then depressed again,and hence numeric values indicative of times or the like are redundantlyset.

SUMMARY OF THE INVENTION

It is a first object of the present invention to provide a remotecontroller system, a remote controller apparatus, and a remotecontroller method, which can reliably provide desired control whilesaving power, as well as to a program for implementing the method and anelectronic apparatus which is remotely controlled.

It is a second object of the present invention to provide a remotecontroller system, a remote controller apparatus, and a remotecontroller method, which can reliably provide desired control even ifthe electronic apparatus has failed to receive part of a control signalwhich is repeatedly transmitted during the depression of a key, as wellas to a program for implementing the method and an electronic apparatuswhich is remotely controlled.

To attain the first object, in a first aspect of the present invention,there is provided a remote control system comprising a remote controlapparatus; and a first apparatus controlled by the remote controlapparatus, and the remote control apparatus comprises at least one keyswitch for remote control, and a first transmitting device thatrepeatedly transmits a control signal corresponding to the key switchwhile the key switch is being operated and that inhibits thetransmission of the control signal in accordance with reception of apredetermined signal from the first apparatus.

According to the first aspect of the present invention, it is possibleto reliably provide desired control while saving power.

Preferably, the remote control apparatus and the first apparatuscommunicate with each other by means of infrared light.

Preferably, the first apparatus comprises a first determination devicethat determines whether the control signal, transmitted by the firsttransmitting device, is suitable for repeated control, and a secondtransmitting device that transmits an inhibition instruction signal forinhibiting the first transmitting device from repeatedly transmittingthe control signal in accordance with a determination by the firstdetermination device.

Preferably, the first apparatus comprises a second determination devicethat determines whether the control signal transmitted by the firsttransmitting device has been normally received, and the secondtransmitting device transmits the inhibition instruction signal and anacknowledgement signal indicative of normal reception of the controlsignal when the second determination device determines that the controlsignal has been normally received, and the first determination devicedetermines that the control signal is unsuitable for repeated control.

Preferably, the remote control apparatus comprises a first determinationdevice that determines whether the control signal corresponding to thekey switch, transmitted by the first transmitting device, is suitablefor repeated control, and a second determination device that determineswhether a response to the control signal has been received from thefirst apparatus, and the transmission device is operable to inhibitrepeated transmission of the control signal when the first determinationdevice determines that the control signal is unsuitable for repeatedcontrol, and the second determination device determines that theresponse has been received.

To attain the first object, in a second aspect of the present invention,there is provided a remote control apparatus that remotely controls afirst apparatus, comprising at least one key switch for remote control,a transmitting device that repeatedly transmits a control signalcorresponding to the key switch while the key switch is being operated,and an inhibition device that inhibits the transmitting device fromrepeatedly transmitting the control signal in accordance with receptionof a predetermined signal from the first apparatus.

To attain the first object, in a third aspect of the present invention,there is provided an electronic apparatus that is remotely controlled bya remote control apparatus, comprising a first determination device thatdetermines whether a same control signal repeatedly transmitted by theremote control apparatus is suitable for repeated control, and atransmitting device that transmits an inhibition instruction signal forinhibiting the repeatedly transmission of the control signal inaccordance with a determination by the first determination device.

Preferably, the electronic apparatus further comprises a seconddetermination device that determines whether the control signal has beennormally received, and the transmitting device transmits the inhibitioninstruction signal and an acknowledgement signal indicative of normalreception of the control signal when the second determination devicedetermines that the control signal has been normally received, and thefirst determination device determines that the control signal isunsuitable for repeated control.

To attain the first object, in a fourth aspect of the present invention,there is provided a remote control method of remotely controlling afirst apparatus by a remote control apparatus, comprising a transmittingstep of repeatedly transmitting a control signal corresponding to a keyswitch for remote control while the key switch is being operated, and aninhibiting step of inhibiting repeated transmission of the controlsignal in accordance with reception of a predetermined signal from thefirst apparatus.

To attain the first object, in a fifth aspect of the present invention,there is provided a remote control method of remotely controlled by aremote control apparatus, comprising a first determination step ofdetermining whether a same control signal repeatedly transmitted by theremote control apparatus is suitable for repeated control, and atransmitting step of transmitting an inhibition instruction signal forinhibiting the repeatedly transmission of the control signal inaccordance with a determination in the first determination step.

To attain the first object, in a sixth aspect of the present invention,there is provided a program for causing a computer to execute a remotecontrol method of remotely controlling a first apparatus by a remotecontrol apparatus, comprising a transmitting module for repeatedlytransmitting a control signal corresponding to a key switch for remotecontrol while the key switch is being operated, and an inhibiting modulefor inhibiting repeated transmission of the control signal in accordancewith reception of a predetermined signal from the first apparatus.

To attain the first object, in a seventh aspect of the presentinvention, there is provided a program for causing a computer to executea remote control method of remotely controlled by a remote controlapparatus, comprising a first determination module for determiningwhether a same control signal repeatedly transmitted by the remotecontrol apparatus is suitable for repeated control, and a transmittingmodule for transmitting an inhibition instruction signal for inhibitingthe repeatedly transmission of the control signal in accordance with adetermination in the first determination module.

To attain the first object, in an eighth aspect of the presentinvention, there is provided a remote control system comprising a remotecontrol apparatus, and a first apparatus controlled by the remotecontrol apparatus, and the first apparatus comprises a firstdetermination device that determines whether a control signal has beennormally received from the remote control apparatus, and a returningdevice that returns an acknowledgement signal indicative of normalreception of the control signal when the determination device determinesthat the control signal has been normally received, and the remotecontrol apparatus comprises at least one key switch for remote control,a transmitting device that repeatedly transmits a control signalcorresponding to the key switch while the key switch is being operated,a second determination device that determines whether the control signalcorresponding to the key switch is suitable for repeated control whenthe acknowledgement signal is returned from the apparatus to becontrolled, and an inhibition device that inhibits the transmittingdevice from repeatedly transmitting the control signal when the seconddetermination device determines that the control signal corresponding tothe key switch is unsuitable for repeated control.

To attain the first object, in a ninth aspect of the present invention,there is provided a remote control apparatus that remotely controls afirst apparatus, comprising at least one key switch for remote control,a transmitting device that repeatedly transmits a control signalcorresponding to the key switch while the key switch is being operated,a determination device that determines whether the control signal issuitable for repeated control when an acknowledgement signal indicativeof normal reception of the control signal is returned from the apparatusto be controlled in response to the control signal, and an inhibitiondevice that inhibits the transmitting device from repeatedlytransmitting the control signal when the determination device determinesthat the control signal is unsuitable for repeated control.

To attain the first object, in a tenth aspect of the present invention,there is provided a remote control method of remotely controlling afirst apparatus by a remote control apparatus, comprising a transmittingstep of repeatedly transmitting a control signal corresponding to a keyswitch for remote control while the key switch is being operated, adetermination step of determining whether the control signal is suitablefor repeated control when an acknowledgement signal indicative of normalreception of the control signal is returned from the apparatus to becontrolled in response to the control signal, and an inhibiting step ofinhibiting repeated transmission of the control signal when it isdetermined in the determination step that the control signal isunsuitable for repeated control.

To attain the first object, in an eleventh aspect of the presentinvention, there is provided a program for causing a computer to executea remote control method of remotely controlling a first apparatus by aremote control apparatus, comprising a transmitting module forrepeatedly transmitting a control signal corresponding to a key switchfor remote control while the key switch is being operated, adetermination module for determining whether the control signal issuitable for repeated control when an acknowledgement signal indicativeof normal reception of the control signal is returned from the apparatusto be controlled in response to the control signal, and an inhibitingmodule for inhibiting repeated transmission of the control signal whenit is determined by the determination module that the control signal isunsuitable for repeated control.

To attain the second object, in a twelfth aspect of the presentinvention, there is provided a remote control system comprising a remotecontrol apparatus, and a first apparatus to be controlled by the remotecontrol apparatus, and the remote control apparatus comprises at leastone key switch for remote control, and a transmitting device thatrepeatedly transmits a control signal corresponding to the key switchwhile the key switch is being operated, and the transmitting device addsa discrimination information for discriminating the control signaltransmitted for a first time by the transmitting device, and the controlsignal transmitted for a second or subsequent time by the transmittingdevice, to the control signal.

According to the twelfth aspect of the present invention, it is possibleto reliably provide desired control even if the electronic apparatus hasfailed to receive part of a control signal which is repeatedlytransmitted during the depression of a key.

Preferably, the transmitting device transmits the control signal bymeans of infrared light.

Preferably, the transmitting device adds a packet number as thediscrimination information.

More preferably, the transmitting device adds a predetermined packetnumber as the discrimination information to the control signaltransmitted for the first time, and cyclically selects and adds one fromamong a plurality of packet numbers, different from the packet numberadded to the control signal transmitted for the first time, to thecontrol signal transmitted for the second or subsequent time.

More preferably, the transmitting device adds a predetermined packetnumber as the discrimination information to the control signaltransmitted for the first time, and adds a predetermined packet numberdifferent from the packet number added to the control signal transmittedfor the first time, to the control signal transmitted for the second orsubsequent time.

Further preferably, the transmitting device adds a predetermined leadercode as the discrimination information to a leading end of the controlsignal transmitted for the first time, and adds a predetermined leadercode different from the leader code added to the control signaltransmitted for the first time, to a leading end of the control signaltransmitted for the second or subsequent time.

Further preferably, the transmitting device adds a predetermined endcode as the discrimination information to a trailing end of the controlsignal transmitted for the first time, and adds a predetermined end codedifferent from the end code added to the control signal transmitted forthe first time, to a trailing end of the control signal transmitted forthe second or subsequent time.

To attain the second object, in an thirteenth aspect of the presentinvention, there is provided a remote control apparatus that wirelesslyand remotely controls a first apparatus, comprising at least one keyswitch for remote control, and a transmitting device that repeatedlytransmits a control signal corresponding to the key switch while the keyswitch is being operated, and the transmitting device adds adiscrimination information for discriminating the control signaltransmitted for a first time by the transmitting device, and the controlsignal transmitted for a second or subsequent time by the transmittingdevice, to the control signal.

To attain the second object, in a fourteenth aspect of the presentinvention, there is provided a remote control method of wirelessly andremotely controlling a first apparatus, comprising a transmitting stepof repeatedly transmitting a control signal corresponding to a keyswitch for remote control while the key switch is being operated, and anaddition step of adding a discrimination information for discriminatingthe control signal transmitted for a first time and the control signaltransmitted for a second or subsequent time to the control signal.

To attain the second object, in a fifteenth aspect of the presentinvention, there is provided a program for causing a computer to executea remote control method of wirelessly and remotely controlling a firstapparatus, comprising a transmitting module for repeatedly transmittinga control signal corresponding to a key switch for remote control whilethe key switch is being operated, and an addition module for adding adiscrimination information for discriminating the control signaltransmitted for a first time and the control signal transmitted for asecond or subsequent time to the control signal.

The above and other objects, features, and advantages of the inventionwill become more apparent from the following detailed description takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing the arrangement of a remote controller systemaccording to a first embodiment of the present invention;

FIG. 2 is a view showing the arrangement of a conventional remotecontroller system;

FIG. 3 is a block diagram schematically showing the construction of aremote controller appearing in FIG. 1;

FIG. 4 is a flow chart showing a control signal transmitting processaccording to the first embodiment;

FIG. 5 is a view showing an example of the structure of a control signalaccording to the first embodiment;

FIG. 6 is a view schematically showing a procedure for carrying outtransmission between the conventional remote controller and an apparatusto be controlled (in the case where a repeat signal is transmittedduring the depression of a key, and the signal is light-shielded fromthe beginning);

FIG. 7 is a view schematically showing a procedure for carrying outtransmission between the remote controller appearing in FIG. 1 and anapparatus to be controlled (in the case where a signal is light-shieldedfrom the beginning);

FIG. 8 is a view schematically showing a procedure for carrying outtransmission between the conventional remote controller and an apparatusto be controlled (in the case where the same signal is transmittedduring the depression of a key, and the signal is light-shielded in themiddle of transmission);

FIG. 9 is a view schematically showing a procedure for carrying outtransmission between the remote controller appearing in FIG. 1 and anapparatus to be controlled (in the case where an ACK signal is returned,and signals are light-shielded in the middle of transmission);

FIG. 10 is a view schematically showing a procedure for carrying outtransmission between a remote controller according to a secondembodiment of the present invention and an apparatus to be controlled(in the case where the packet numbers of second and subsequent controlsignals are fixed at “01”);

FIG. 11 is a view showing an example of the structure of a controlsignal according to a third embodiment of the present invention;

FIGS. 12A and 12B are views showing examples of the driving waveform ofa leader code in the control signal appearing in FIG. 11, in which FIG.12A shows a first leader code which is used for data to be transmittedfor the first time upon depression of a key, and FIG. 12B shows a secondleader code which is used for data to be transmitted for the second andsubsequent times during depression of a key;

FIG. 13 is a flow chart showing a control signal transmitting processaccording to the third embodiment;

FIG. 14 is a view schematically showing a procedure for carrying outtransmission between a remote controller and an apparatus to becontrolled according to a fourth embodiment of the present invention (inthe case where a repeat stop signal as well as an “ACK” signal arereturned);

FIG. 15 is a flow chart showing a control signal transmitting processaccording to the fourth embodiment;

FIG. 16 is a flow chart showing the operation of an apparatus to becontrolled according to the fourth embodiment;

FIG. 17 a view schematically showing a procedure for carrying outtransmission between a remote controller and an apparatus to becontrolled according to a fifth embodiment of the present invention (inthe case of multi frames);

FIG. 18 is a flow chart showing a control signal transmitting processaccording to the fifth embodiment;

FIG. 19 is a continued part of the flow chart in FIG. 18;

FIG. 20 is a flow chart showing a control signal transmitting processaccording to a sixth embodiment of the present invention (in the casewhere a remote controller voluntarily determines whether to repeatedlytransmit a control signal); and

FIG. 21 is a view showing an example of the structure of a conventionalcontrol signal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference tothe accompanying drawings showing preferred embodiments thereof.

FIG. 1 is a view showing the arrangement of a remote control systemaccording to a first embodiment of the present invention. In FIG. 1,reference numeral 1 denotes a remote controller, and reference numeral50 denotes an apparatus to be controlled.

The remote controller 1 includes a keyboard 3, a liquid crystal display2, an infrared light emitting section (infrared light emitting diode) 4,and an infrared light receiving section (photodiode) 5. The apparatus 50to be controlled (hereinafter referred to as the “controlled apparatus50”) includes an infrared light receiving section 52 for receiving aninfrared light signal from the remote controller 1, an infrared lightemitting section 53 for transmitting an infrared light signal to theremote controller 1, and a microprocessor (MPU) 51 which controlsprocessing of the transmitted and received signals and component parts,not shown, of the controlled apparatus 50.

FIG. 2 is a view showing the arrangement of a conventional remotecontrol system. In FIG. 2, reference numeral 30 denotes a remotecontroller, and reference numeral 60 denotes an apparatus to becontrolled.

The remote controller 30 includes a keyboard 33, a liquid crystaldisplay 31, and an infrared emitting section (infrared emitting diode)32. The apparatus 60 to be controlled (hereinafter referred to as the“controlled apparatus 60”) includes an infrared light receiving section62 for receiving an infrared light signal from the remote controller 1,and a microprocessor (MPU) 61 which controls processing of the receivedsignal and component parts, not shown, of the controlled apparatus 60.

Namely, the remote control system according to the present inventioncarries out two-way signal transmission, not one-way signal transmissionas in the prior art.

FIG. 3 is a block diagram schematically showing the construction of theremote controller 1 appearing in FIG. 1.

In FIG. 3, reference numeral 20 denotes a microprocessor (MPU) includinga program memory (ROM) 7 which stores programs for carrying out variouskinds of processing, described later, and a program counter 9.Instructions stored at addresses designated by the program counter 9 aredecoded by an instruction decode controller 8 to control component partsin synchronism with a predetermined timing clock, not shown.

For example, data stored in a data memory 6 implemented by a RAM istransmitted to an arithmetic-logic unit (ALU) 11 via a data bus 12 tocause the same to perform arithmetic processing, and the arithmeticprocessing result is stored in the data memory 6 via the data bus 12, orthe data stored in the data memory 6 is transmitted to a displaydecoder/driver 10 and displayed on the liquid crystal display 2.

Further, a key scan signal is output to the keyboard 3 via an outputport 14 to cause the same to carry out key-scanning, and if any key onthe keyboard 3 has been depressed, a key operation signal correspondingto the depressed key is captured via an input port 13 and stored in thedata memory 6 via the data bus 12, so that processing suitable for eachkey (exactly, a key switch) is performed in accordance with a programstored in the program memory 7.

Further, signal data for controlling the apparatus, which is stored inthe data memory 6, is transmitted to an output port 18, and a driver 17drives the infrared emitting diode 4 to convert the signal data into aninfrared light signal and transmits the same to the controlled apparatus50.

Further, a response signal or the like of infrared light from thecontrolled apparatus 50 is received by the photodiode 5, and capturedinto an input port 15 via a light receiving amplifier 16, so that theresponse signal or the like is stored in the data memory 6 via the bus12 and displayed on the liquid crystal display 2, or various kinds ofoperation control are provided.

Next, a description will be given of a control signal transmittingprocess according to the present embodiment with reference to a flowchart of FIG. 4.

In a step S1, display processing is carried out, in which data to bedisplayed is selected from data in the data memory 6 appearing in FIG. 3and is displayed. Next, it is determined whether there has been a keyinput or not (step S2), and if there has been no key input, the processreturns to the step S1, so that the steps S1 and S2 are executed again.

If there has been a key input, the process proceeds to a step S3 whereina light signal as a control signal corresponding to the key input istransmitted. Referring to FIG. 5, a description will be now given of thecode system of one frame of the light signal.

FIG. 5 is a view showing an example of the structure of a control signalaccording to the present embodiment.

In FIG. 5, reference numeral 501 denotes a leader code, and referencenumeral 502 denotes a custom code. They are identical with those of theabove described prior art, and description thereof is therefore omitted.

Reference numeral 503 denotes a code which designates one of a pluralityof controlled apparatuses 50, as an object to be controlled, and a hostnumber for identifying the designated controlled apparatus 50 is set asthe code 503. Different host numbers are assigned to a plurality ofcontrolled apparatuses 50, and hence even if they are of the samemanufacturer and the same model, it is possible to selectively controlone among them.

Reference numeral 504 denotes a code for enabling any one controlledapparatus 50 to receive a control signal via a selected one of aplurality of remote controllers of the same manufacturer, and a remotecontrol number assigned to the selected remote controller is set as thecode 504.

Reference numeral 505 denotes a communication type code which isindicative of whether data to be transmitted is comprised of one frame(referred to as a single frame) or a plurality of frames (referred to asmulti frames), and a code “00” is set for a single frame. If data to betransmitted is comprised of multi frames, a number “01” is set for thefirst frame, a number “10” is set for intermediate frames, and a number“11” is set for the last frame, so that the code 505 as well as a packetnumber, described later, can be used for managing the properties ofrespective frames.

Reference numeral 506 denotes a code indicative of a packet number, andis comprised of 2 bits indicative of the order of data to be transmitted(command).

If data to be transmitted is single-frame data, a code “00” is assignedas the packet number 506 to the first single frame. Three codes “01”,“10”, and “11” other than the code “00” are cyclically assigned in theorder of “01”→“10”→“11”→“01”→“10” to the second and subsequent singleframes which are repeatedly transmitted during continuous depression ofa key, so that the first single frame (command) and the second andsubsequent single frames (commands) can be discriminated from eachother. It should be noted that one or two of the codes “01”, “10”, and“11” may be fixedly assigned to the second and subsequent single frames.

On the other hand, if data to be transmitted is multi-frame data, thecodes “00”, “01”, “10”, and “11” are cyclically assigned in the order of“00”→“01”→“10”→“11”→“00”→“01” as the packet number 506 to multipleframes simply as in the case of a quaternary counter. This is because inremote control, the order of data to be transmitted is never changed asis distinct from packet data flowing on a signal line of a LAN (LocalArea Network) or the like, and hence each frame among multiple framescan be identified even if a small number of numeric values are repeated.

Reference numeral 507 denotes data length information indicative of thelength of data (command); 508, data (command); 509, a check sum; and510, an END code.

In a step S3 in FIG. 4, the light signal in the format as describedabove is transmitted, and the count values of a first timer and a secondtimer, not shown, provided on the data memory 6 are reset.

Then, it is determined whether or not the key is being continuouslydepressed (step S4). If the key is being continuously depressed, theprocess proceeds to a step S5 wherein a determination as to whether apredetermined period of time has elapsed or not is made by determiningwhether the count value of the first timer has become equal to apredetermined value or not. If the predetermined period of time has notelapsed, the count value of the first timer is incremented by one (stepS6), and the process returns to the step S4.

On the other hand, if the predetermined period of time has elapsed, theprocess proceeds to a step S7 wherein 1 is added to the value of the2-bit packet number 506. Then, it is determined in a step S8 whether theresulting 2-bit value is “00” or not. If the resulting value is “00”,the packet number 506 is set to “01” in a step S9, and a light signal istransmitted and the first timer is reset in a step S10. The process thenreturns to the step S4.

On the other hand, if the resulting packet number is not “00”, theprocess proceeds to the step S10 with the step S9 being skipped, so thata light signal is transmitted while the 2-bit packet number obtained byaddition in the step S7 is maintained, and the first timer is reset.

As a result of the processing described above, while the key is beingdepressed, the packet number is cyclically changed to “01”, “10”, “11”,and “01”, and light signals are sequentially transmitted atpredetermined time intervals.

If it is determined in the step S4 that the key is not continuouslydepressed or the key is released, a determination as to whether apredetermined period of time has elapsed or not is made by determiningwhether the count value of the second timer has become equal to apredetermined value or not so as to determine whether the key has beenreleased for the predetermined period of time or not, i.e. whether thekey has been surely released or not (step S11). If the predeterminedperiod of time has not elapsed, the count value of the second timer isincremented by one (step S12), and the process returns to the step S4.On the other hand, if the count value of the second timer has becomeequal to the predetermined value, i.e. the predetermined period of timehas elapsed, it is determined that the key has been surely released, andthe process returns to the step S1.

A description will now be given of differences between the presentembodiment and the prior art with reference to FIGS. 6 and 7.

FIG. 6 is a view schematically showing a procedure for carrying outcommunication between the remote controller 30 which repeatedlytransmits a repeat signal while a key switch is continuously depressedand the controlled apparatus 60 according to the prior art. When anarbitrary key switch SW3 of the remote controller 30 (refer to FIG. 2)is depressed, an infrared light signal 601 with a format in FIG. 21A istransmitted.

However, if the infrared light signal 601 is not received by thecontrolled apparatus 60 due to the presence of an obstacle or the likeor the direction in which the remote controller 30 is placed, the nextsignal 602 which is transmitted upon continuous depression of the keyswitch SW3 is a repeat signal with a format in FIG. 21C, and thus, arepeat signal 604 is received first by the controlled apparatus 60 afterthe cause of impossibility to receive a signal is eliminated. Therefore,the controlled apparatus 60 cannot recognize what kind of instructedoperation should be repeated, and hence makes the repeat signals 604,605, and 606 through.

FIG. 7 is a view schematically showing a procedure for carrying outcommunication between the remote controller 1 and the controlledapparatus 50 according to the present embodiment. When an arbitrary keyswitch SW1 of the remote controller 1 (refer to FIG. 1) is depressed, aninfrared light signal 701 with a format in FIG. 5 is transmitted.

However, if the infrared light signal 701 is not received by thecontrolled apparatus 50 due to the presence of an obstacle or the likeor the direction in which the remote controller 30 is placed, the nextsignal 702 which is transmitted upon continuous depression of the keyswitch SW3 is a light signal with the same format as the signal 701 andthe packet number 506 having being changed to “01”.

However, if neither the light signal 702 nor a subsequently transmittedlight signal 703 is not received by the controlled apparatus 50 and alight signal 704 is received first by the controlled apparatus 50, thelight signal 704 has the same format as the light signal 701 and thepacket number 506 having been changed to “11”.

The light signal 704 includes the host number 503, the number of aremote controller as a transmission source, the data 508 as commandinformation indicated by the key switch SW1, and so forth, and hence thecontrolled apparatus 50 can recognize which remote controller hastransmitted what command, and then provide suitable control.

Thereafter, if the key switch SW1 is continuously depressed, the remotecontroller 1 transmits light signals 705 and 706 with the same format asthe light signal 701 and the packet numbers 506 having been changed to“01” and “10” at predetermined time intervals, and the controlledapparatus 50 carries out so-called a repeating operation.

In this way, the present embodiment can solve the problem of the priorart that if the apparatus to be controlled fails to receive the firstsignal, it cannot recognize what kind of instructed operation should berepeated.

FIG. 8 is a view schematically showing a procedure for carrying outcommunication between the remote controller 30 according to the priorart which transmits a light signal with a format suitable for a keyswitch when the key switch is continuously depressed, and the controlledapparatus 60 according to the prior art. Even if the controlledapparatus 60 fails to receive the first light signal, suitable controlcan be provided insofar as the Nth signal can be received since the samesignal is transmitted each time, and hence the problem described abovewith reference to FIG. 6 does not arise.

However, if a light signal is interrupted by an obstacle during thedepression of a key, another problem arises as described below.

Specifically, when an arbitrary key switch SW4 of the remote controller30 (refer to FIG. 2) is depressed, a light signal 801 with the format inFIG. 21A is transmitted. If normally receiving the light signal 801, thecontrolled apparatus 60 provides control, not shown, corresponding tothe key switch SW4. Since the key switch SW4 is continuously depressed,the remote controller 30 transmits a light signal 802 with the sameformat as the light signal 801 at predetermined time intervals.

If the received light signal 802 is a signal corresponding to repeatedprocessing, the controlled apparatus 60 carries out suitable processing(for example, volume increase or decrease), and if the received lightsignal 802 is not a signal corresponding to repeated processing but asignal corresponding to e.g. channel setting, the controlled apparatus60 carries out processing such as making the light signal 802 through.

Here, it is assumed that light signals 803, 804, 805, and 806 aretransmitted due to continuous depression of the key switch SW4, but thelight signals 803, 804, and 805 are not received by the controlledapparatus 60 due to an obstacle or the like, and only the light signal806 is received by the controlled apparatus 60.

In this case, since the format in FIG. 21A does not include informationindicative of the relationship between sequential light signals such asa packet number, the controlled apparatus 60 regards the received lightsignal 806 as a light signal corresponding to a key which is depressedagain after being released. Specifically, when the reception of a signalis interrupted due to an obstacle or the like during the depression of akey, it is determined that the key has been released, and then if theobstacle or the like is removed and the next signal is received, it isdetermined that the key has been depressed again, and as a result, thesame processing is carried out as in the case where key input is madetwice.

In this case, if the light signal 806 corresponds to repeated processingor channel setting, so-called overwriting is carried out for repeatedprocessing or channel setting. If the light signal 806 is a light signalfor setting a numeric value or the like such as a time which varies withtime, the same processing is carried out as in the case where key inputis made twice, and numeric values or the like are redundantly set.

FIG. 9 is a view schematically showing a procedure for carrying outcommunication between the remote controller 1 and the controlledapparatus 50 according to the present embodiment. When an arbitrary keyswitch SW2 of the remote controller 1 (refer to FIG. 1) is depressed, alight signal 901 with the format in FIG. 5 is transmitted. If normallyreceiving the light signal 901, the controlled apparatus 50 returns anACK signal 902 which acknowledges normal reception to the remotecontroller 1, and provides control, not shown, corresponding to the keyswitch SW2.

Since the key switch SW2 is continuously depressed, the remotecontroller 1 transmits a light signal 903 with the same format as thelight signal 901 and with the packet number 506 having been changed to“01” at predetermined time intervals. If the received light signal 903is a signal corresponding to repeated processing, the controlledapparatus 50 carries out suitable processing (for example, volumeincrease or decrease) and returns an ACK signal 904, and if the receivedlight signal 903 is not a signal corresponding to repeated processingbut a signal corresponding to e.g. channel setting, the controlledapparatus 50 carries out processing such as making the light signal 903through, and returns the ACK signal 904.

Here, it is assumed that light signals 905, 906, 907, and 908 aretransmitted due to continuous depression of the key switch SW2, but thelight signals 905, 906, and 907 are not received by the controlledapparatus 50 due to any obstacle or the like, and only the light signal908 is received by the controlled apparatus 50.

In this case, the received light signal 908 is a light signal with thesame format as the light signal 901 and the packet number 506 havingbeen changed to “10”, and the controlled apparatus 50 can recognize thatthe light signal 908 is a continued part of the interrupted signalcontinuing from the light signal 901. The light signal 908 includes acommand corresponding to the key switch SW2 as the data 508 (refer toFIG. 5) as well as a host number, the number of a remote controller as atransmission source, and so forth.

Therefore, if the light signal 908 corresponds to repeated processing,the remote controller 1 carries out suitable processing (for example,volume increase or decrease) and returns an ACK signal 909, and if thelight signal 908 does not correspond to repeated processing butcorresponds to e.g. setting of an input numeric value), the remotecontroller 1 makes the light signal 908 through to prevent redundantsetting, and returns the ACK signal 909.

It should be noted that when normally receiving a signal from the remotecontroller 1, the controlled apparatus 50 returns an ACK signal, but maynot return an ACK signal.

A description will now be given of a second embodiment of the presentinvention.

In the above described first embodiment, if a key is continuouslydepressed, the packet number “00” is assigned to the first light signal,and the packet numbers “01”, “10”, “11”, “01” . . . are cyclicallyassigned to the second and subsequent light signals, but in the secondembodiment, a packet number “01” is fixedly assigned to the second andsubsequent light signals although a packet number “00” is assigned tothe first signal as is the case with the first embodiment.

FIG. 10 is a view schematically showing a procedure for carrying outcommunication between the remote controller 1 according to the secondembodiment and the controlled apparatus 50. When an arbitrary key switchSW2 of the remote controller 1 (refer to FIG. 1) is depressed, aninfrared light signal 1101 with the format in FIG. 5 is transmitted. Ifnormally receiving the infrared light signal 1101, the controlledapparatus 50 returns a return signal ACK signal 1102 which acknowledgesnormal reception to the remote controller 1, and provides control, notshown, corresponding to the key switch SW2.

Since the key switch SW2 is continuously depressed, the remotecontroller 1 transmits a light signal 1103 with the same format as theinfrared light signal 1101 and with the packet number 506 having beenchanged to “01” at predetermined time intervals. Thereafter, while thekey switch SW2 is continuously depressed, the remote controller 1continues to transmit the light signal 1103 with the same format as theinfrared light signal 1101 and with the packet number 506 having beenchanged to “01”.

If the continuously received light signal 1103 is a signal correspondingto repeated processing, the controlled apparatus 50 carries out suitableprocessing (for example, volume increase or decrease) and returns an ACKsignal 1104, and if the received light signal 1103 is not a signalcorresponding to repeated processing but a signal corresponding to e.g.channel setting, the controlled apparatus 50 carries out processing suchas making the light signal 1103 through, and returns the ACK signal1104.

Here, it is assumed that light signals 1105, 1106, 1107, and 1108 aretransmitted due to continuous depression of the key switch SW2, but thelight signals 1105, 1106, and 1107 are not received by the controlledapparatus 50 due to any obstacle or the like, and only the light signal1108 is received by the controlled apparatus 60.

In this case, the received light signal 1108 is a light signal with thesame format as the light signal 1101 and the packet number 506 havingbeen changed to “01”, and the controlled apparatus 50 can recognize thatthe light signal 1108 is a continued part of the interrupted signalcontinuing from the light signal 1101. The light signal 1108 includes acommand corresponding to the key switch SW2 as the data 508 (refer toFIG. 5) as well as a host number, the number of a remote controller as atransmission source, and so forth.

Therefore, if the light signal 1108 is a signal corresponding torepeated processing, the remote controller 1 carries out suitableprocessing (for example, volume increase or decrease) and returns an ACKsignal 1109, and if the light signal 1108 is not a signal correspondingto repeated processing but a signal corresponding to e.g. setting of aninput numeric value), the remote controller 1 makes the light signal1108 through to prevent redundant setting, and returns the ACK signal1109.

It should be noted that in the second embodiment, when receiving asignal from the remote controller 1, the controlled apparatus 50 returnsan ACK signal, but may not return an ACK signal.

A description will now be given of a third embodiment of the presentinvention.

One frame of a light signal transmitted from the remote controller 1 isformatted as shown in FIG. 5 according to the first and secondembodiments, but is formatted as shown in FIG. 11 according to the thirdembodiment.

In FIG. 11, reference numeral 1201 denotes a leader code; 1202, a customcode; 1203, a host number; 1204, a remote controller number; 1205, acommunication type code indicative of whether data to be transmitted iscomprised of one frame or a plurality of frames; 1206, a data lengthcode indicative of the length of data (command) 1207; 1207, data(command); 1208, a check sum; and 1209, an END code.

Specifically, the frame of a light signal according to the thirdembodiment is configured by removing a packet number from the frame of alight signal according to the first and second embodiments.

FIGS. 12A and 12B are views showing examples of the driving waveform ofthe leader code 1201 in FIG. 11, which are applied to the LED 4, inwhich FIG. 12A shows a first leader code which is used for data to betransmitted for the first time upon depression of a key, and FIG. 12Bshows a second leader code which is used for data to be transmitted forthe second and subsequent times during depression of a key.

The first leader code in FIG. 12A, which is used for a light signaltransmitted for the first time, is identical with the one according tothe first and second embodiments described with reference to FIG. 5, andis comprised of a signal present section with a duration of 8T and asignal absent section with a duration of 4T. The second leader code inFIG. 12B, which is used for light signals transmitted for the second andsubsequent times, is comprised of a signal present section with aduration of 8T and a signal absent section with a duration of 8T.

As described above, in the third embodiment, different leader codes areselectively used for a light signal transmitted for the first time andfor light signals transmitted subsequently, so that they have the samefunction as the packet number, i.e. a function of making a determinationas to the continuity of signals by discriminating between a light signaltransmitted for the first time and light signals transmittedsubsequently.

It should be noted that the period of time required for transmission ofa packet number removed in the third embodiment is “2T” for a bit “0”,and is “4T” for a bit “1”, and the period of time required for 2 bitsvaries within the range between 4T and 8T according to packet numbers.

On the other hand, the period of time required for transmission of thesecond leader code (16T) in FIG. 12B in a light signal transmitted forthe second or subsequent time is longer only by 4T than the period oftime required for transmission of the first leader code (12T) in FIG.12A in a light signal transmitted for the first time, i.e. the period oftime required for transmission of a conventional leader code. Therefore,it is possible to transmit a light signal with one frame within the sameperiod of time or a shorter period of time as compared with the casewhere a light signal transmitted for the first time and light signalstransmitted subsequently are discriminated from each other according topacket numbers.

It should be noted that the function of discriminating between a lightsignal transmitted for the first time and light signals transmittedsubsequently and making a determination as to the continuity of thelight signals may be realized by changing the END code.

A description will now be given of a control signal transmitting processaccording to the third embodiment with reference to a flow chart of FIG.3.

As shown in FIG. 13, display processing is carried out in a step S1301,in which data to be displayed is selected from data in the data memory 6appearing in FIG. 3 and is displayed. Next, it is determined whetherthere has been a key input or not (step S1302), and if there has been nokey input, the process returns to the step S1301, so that the stepsS1301 and S1302 are executed again.

If there has been a key input, the process proceeds to a step S1303wherein a light signal corresponding to the input key is transmitted,and the count values of the first timer and the second timer provided onthe data memory 6 are reset. The first leader code in FIG. 12A is usedas a leader code for the light signal transmitted in the step S1303since it is transmitted for the first time.

Then, it is determined whether or not the corresponding key is beingcontinuously depressed (step S1304). If the key is being continuouslydepressed, the process proceeds to a step S1305 wherein a determinationas to whether a predetermined period of time has elapsed or not is madeby determining whether the count value of the first timer has becomeequal to a predetermined value or not. If the predetermined period oftime has not elapsed, the count value of the first timer is incrementedby one (step S1306), and the process then returns to the step S1304.

On the other hand, if the predetermined period of time has elapsed, alight signal corresponding to the input key is transmitted, and thecounter value of the first timer is reset (step S1307). The secondleader code in FIG. 12B is used as a leader code for the light signaltransmitted in the step S1307 since it is transmitted for the second orsubsequent time.

Since the process thus returns from the step S1307 to the step S1304,the same light signal as the one transmitted in the step S1307 isthereafter continuously transmitted at predetermined time intervalsclocked by the first timer while the key is being depressed.

If it is determined in the step S1304 that the key has been released, adetermination as to whether the count value of the second timer hasbecome equal to a predetermined value or not is determined so as todetermine whether the key has been released for the predetermined periodof time or not, i.e. whether the key has been surely released or not(step S1308). If the predetermined period of time has not elapsed, thecount value of the second timer is incremented by one (step S1309), andthe process returns to the step S1304. On the other hand, if thepredetermined period of time has elapsed, it is determined that the keyhas been surely released, and the process returns to the step S1301.

A description will now be given of a fourth embodiment of the presentinvention.

In the fourth embodiment, even if a key is continuously depressed,repeated transmission of a control signal (light signal) correspondingto the key is not carried out depending on the type of the key.

Namely, depending on the type of a depressed key, the same controlsignal corresponding to the key does not have to be repeatedlytransmitted during the depression of the key insofar as the controlsignal corresponding to the key is properly transmitted once to thecontrolled apparatus 50.

For example, a control signal indicative of an instruction for switchingchannels by designating a TV channel number, a control signal indicativeof an instruction for switching between TV input and video input, acontrol signal indicative of an instruction for selectively turningon/off a function switch, and so forth are not suitable for repeatedoperation carried out by the controlled apparatus 50, and hence as tokeys for transmitting such control signals, the same control signal doesnot have to be repeatedly transmitted even if the keys are continuouslydepressed.

Therefore, in the fourth embodiment, when an “ACK” signal or the likeindicative of normal reception is returned in response to such a controlsignal, repeated transmission of the control signal is not carried out.

The inhibition of repeated transmission saves power for the remotecontroller 1. Further, due to the elimination of unnecessary infraredemission, the period of time for which no infrared is emitted isincreased, and hence even if another apparatus to be controlled byinfrared is located in the vicinity of the controlled apparatus 50, itis possible to prevent an infrared communication conflict and prevente.g. malfunction of the apparatuses to be controlled.

FIG. 14 is a view schematically showing a procedure for carrying outcommunication between the remote controller 1 and the controlledapparatus 50 according to the fourth embodiment. When an arbitrary keyswitch SW2 of the remote controller 1 (refer to FIG. 1) is depressed, alight signal 1501 with the format in FIG. 5 is transmitted. If normallyreceiving the light signal 1501, the controlled apparatus 50 returns an“ACK” signal which acknowledges normal reception and a repeat stopsignal 1502 to the remote controller 1, and provides control, not shown,corresponding to the key switch SW2.

The remote controller 1 recognizes that the controlled apparatus 50 hasnormally received the light signal 1501 due to the reception of the“ACK” signal, and stops transmitting a control signal corresponding tothe key switch SW2 due to the reception of the repeat stop signal 1502even if the key switch SW2 is continuously depressed.

In the fourth embodiment, the controlled apparatus 50 has a function ofdetermining whether a received control signal is suitable for repeatedcontrol or not; the controlled apparatus 50 is configured to return arepeat stop signal when it determines that the received control signalis not suitable for repeated control. This function is executed by theMPU 51 in accordance with the corresponding program.

A description will now be given of a control signal transmitting processaccording to the fourth embodiment with reference to a flow chart ofFIG. 15

As shown in FIG. 15, display processing is carried out in a step S1501,in which data to be displayed is selected from data in the data memory 6appearing in FIG. 3 and is displayed. Next, it is determined whetherthere has been a key input or not (step S1502), and if there has been nokey input, the process returns to the step S1501, so that the stepsS1501 and S1502 are executed again. If there has been a key input, theprocess proceeds to a step S1503 wherein a light signal corresponding tothe input key is transmitted, and the count values of the first timerand the second timer provided on the data memory 6 are reset. The firstleader code in FIG. 12A is used as a leader code for the light signaltransmitted in the step S1303 since it is transmitted for the firsttime.

Then, it is determined whether or not an “ACK” signal has been returnedfrom the controlled apparatus 50 (step S1504). If the “ACK” signal hasnot been returned, it is then determined whether or not thecorresponding key is being continuously depressed (step S1505). If thekey is not being continuously depressed, the process proceeds to a stepS1510, described later.

On the other hand, if the key is being continuously depressed, theprocess proceeds to a step S1506 wherein a determination as to whether apredetermined period of time has elapsed or not is made by determiningwhether the count value of the first timer has become equal to apredetermined value or not. If the predetermined period of time has notelapsed, the count value of the first timer is incremented by one (stepS1507), and the process then returns to the step S1504.

On the other hand, if the predetermined period of time has elapsed, alight signal corresponding to the input key is transmitted, and thecounter value of the first timer is reset (step S1508). The secondleader code in FIG. 12B is used as a leader code for the light signaltransmitted in the step S1508 since it is transmitted for the second orsubsequent time.

If it is determined in the step S1504 that the “ACK” signal has beenreturned, it is determined whether or not a repeat stop signal and the“ACK” signal have been simultaneously returned (step S1509). If only the“ACK” signal has been returned, the process proceeds to the step S1505wherein it is determined whether the key is being continuously depressedor not.

As described above, since the process returns from the step S1508 to thestep S1504, the same light signal as the one transmitted in the stepS1508 is thereafter continuously transmitted at predetermined timeintervals clocked by the first timer while the key is being depressed.Therefore, even if the light signal is temporarily blocked by anobstacle or the like, it can be surely received by the controlledapparatus 50 when the obstacle or the like is removed.

Further, as described above, the controlled apparatus 50 does not returna repeat stop signal in response to a control signal suitable forrepeated control, and hence a control signal relating to an operationsuitable for repeated control such as volume control is repeatedlytransmitted by continuously depressing the corresponding key.

If it is determined in the step S1509 that the repeat stop signal andthe “ACK” signal have been simultaneously returned, a determination asto whether or not the key has been released is made (step S1510). If thekey has not been released, the determination is continuously made.

On the other hand, if the key has been released, whether the count valueof the second timer has become equal to a predetermined value or not isdetermined so as to determine whether the key has been released for thepredetermined period of time or not, i.e. whether the key has beensurely released or not (step S1511). If the count value of the secondtimer has not become equal to the predetermined value, the count valueof the second timer is incremented by one (step S1512), and the processreturns to the step S1510. On the other hand, if the count value of thesecond timer has become equal to the predetermined value, it isdetermined that the key has been surely released, and the processreturns to the step S1501.

As a result, in the case where a repeat stop signal as well as an “ACK”signal have been received, even if a key corresponding to a controlsignal unsuitable for repeated control is thereafter continuouslydepressed, repeated transmission of the control signal corresponding tothe key is not carried out.

Next, a description will be given of the operation of the controlledapparatus 50 according to the fourth embodiment with reference to a flowchart of FIG. 16.

As shown in FIG. 16, the controlled apparatus 50 waits for reception ofinfrared light by the infrared light receiving section 52 (refer toFIG. 1) (step S1601). Upon receipt of infrared light, the controlledapparatus 50 determines whether or not the received infrared light is acontrol signal directed to the controlled apparatus 50, and the controlsignal has been normally received (step S1602). If the control signaldirected to the controlled apparatus 50 has not been normally received,the process returns to the step S1601.

On the other hand, if the control signal directed to the controlledapparatus 50 has been normally received, the controlled apparatus 50determines whether the control signal is suitable for repeated controlor not (step S1603). If the control signal is suitable for repeatedcontrol, the controlled apparatus 50 returns an “ACK” signal to theremote controller 1 (step S1604), and carries out processing (operation)according to the control signal (step S1606). The process then returnsto the step S1601 wherein the next reception of infrared is awaited.

On the other hand, if the control signal is not suitable for repeatedcontrol, the controlled apparatus 50 returns a repeat stop signal aswell as the “ACK” signal to the remote controller 1 (step S1605), andcarries out processing (operation) according to the control signal (stepS1606). The process then returns to the step S1601 wherein the nextreception of infrared is awaited.

In the above description, an infrared light signal from the remotecontroller 1 is formatted as shown in FIG. 11, but may be formatted asshown in FIG. 5. In this case, in the step S1503 in FIG. 15, a signalwith a packet number “00” is transmitted so as to indicate that thesignal is transmitted for the first time, and in the step S1508, asignal with a packet number other than the packet number “00” istransmitted.

A description will now be given of a fifth embodiment of the presentinvention.

In the above described first to fourth embodiments, it is assumed thatonly a control signal with a single frame is transmitted, but in thefifth embodiment, it is assumed that not only a control signal with asingle frame but also a control signals with multi frames istransmitted.

FIG. 17 is a view schematically showing a procedure for carrying outcommunication between a remote controller and an apparatus to becontrolled according to the fifth embodiment.

As shown in FIG. 17, when a key switch SW3 (refer to FIG. 3)corresponding to a control signal with multi frames is depressed, theremote controller 1 transmits an infrared light signal 1701 whosecommunication type 505 is “01” indicative of the first frame and whosepacket number 506 is “00” in the format in FIG. 5. Upon normal receiptof the light signal 1701, the controlled apparatus 50 returns an “ACK”signal 1702 which acknowledges normal reception to the remote controller1, and stores the received light signal 1701 in a memory thereof to waitfor reception of the next frame data.

Upon receipt of the “ACK” signal 1702, the remote controller 1 transmitsthe next frame data as a light signal 1703 in the same format as theprevious frame, and whose communication type 505 is “00” indicative ofan intermediate frame and packet number 506 has been changed to “01”.

However, if the light signal 1703 has not been received by thecontrolled apparatus 50 due to the presence of an obstacle or the like,and hence the “ACK” signal has not been returned from the controlledapparatus 50, the remote controller 1 transmits a light signal 1704 justidentical with the light signal 1703.

Here, if the obstacle or the like has been removed, and the controlledapparatus 50 normally receives the light signal 1704, the controlledapparatus 50 returns an “ACK” signal 1705 and stores the light signal1704 as the second frame data in the memory.

Upon receipt of the “ACK” signal, the remote controller 1 transmits thethird frame data as a light signal 1706 whose communication type 505 is“10” indicative of an intermediate frame and packet number 506 has beenchanged to “10”. Upon normal reception of the light signal 1706, thecontrolled apparatus 50 returns an “ACK” signal 1707 to the remotecontroller 1, and stores the light signal 1706 as the third frame datain the memory.

Upon receipt of the “ACK” signal 1707, the remote controller 1 transmitsfourth frame data i.e. final frame data as a light signal 1708 whosecommunication type 505 is “11” indicative of the last frame and thepacket number 506 has been changed to “11”. Upon normal reception of thelight signal 1708, the controlled apparatus 50 returns an “ACK” signal1709 to the remote controller 1, and stores the light signal 1708 as thefourth frame data in the memory. Then, the controlled apparatus 50provides suitable control according to the data which has beensequentially stored in the memory.

A description will now be given of a control signal transmitting processaccording to the fifth embodiment with reference to flow charts of FIGS.18 and 19.

As shown in FIG. 18, in a step S801, display processing is carried out,in which data to be displayed is selected from data in the data memory 6appearing in FIG. 3 and is displayed. Next, it is determined whetherthere has been a key input or not (step S1802), and if there has been nokey input, the process returns to the step S1801, so that the stepsS1801 and S1802 are executed again.

If there has been a key input, whether a control signal to betransmitted is a single-frame control signal or not is determinedaccording to the key input (step S1803). If the control signal to betransmitted is a single-frame control signal, the process proceeds to astep S1804 wherein a single-frame control signal (light signal)corresponding to the key input is transmitted, and the count values ofthe first timer and the second timer provided on the data memory 6 arereset. A code “00” is assigned as a packet number for the light signaltransmitted in the step S1804 since it is transmitted for the firsttime.

Then, it is determined whether or not an “ACK” signal has been returnedfrom the controlled apparatus 50 (step S1805). If the “ACK” signal hasnot been returned, it is then determined whether or not thecorresponding key is being continuously depressed (step S1806). If thekey is not being continuously depressed, the process proceeds to a stepS1811, described later.

On the other hand, if the key is being continuously depressed, theprocess proceeds to a step S1807 wherein a determination as to whether apredetermined period of time has elapsed or not is made by determiningwhether the count value of the first timer has become equal to apredetermined value or not. If the predetermined period of time has notelapsed, the count value of the first timer is incremented by one (stepS1808), and the process then returns to the step S1805.

On the other hand, if the predetermined period of time has elapsed, alight signal corresponding to the input key is transmitted, and thecounter value of the first timer is reset (step S1809), and then theprocess returns to the step S1805. A code “01” is fixedly assigned as apacket number for the light signal transmitted in the step S1809 sinceit is transmitted for the second or subsequent time.

If it is determined in the step S1805 that the “ACK” signal has beenreturned, it is determined whether or not a repeat stop signal and the“ACK” signal have been simultaneously returned (step S1810). If only the“ACK” signal has been returned, the process proceeds to the step S1806wherein it is determined whether the key is being continuously depressedor not.

As described above, since the process returns from the step S1809 to thestep S1805, the same light signal as the one transmitted in the stepS1809 is thereafter continuously transmitted at predetermined timeintervals clocked by the first timer until the “ACK” signal is returnedwhile the key is being depressed. Therefore, even if the light signal istemporarily blocked by an obstacle or the like, the light signal can besurely received by the controlled apparatus 50 when the obstacle or thelike is removed.

Further, as described above, the controlled apparatus 50 does not returna repeat stop signal in response to a control signal suitable forrepeated control, and hence a control signal relating to an operationsuitable for repeated control such as volume control is repeatedlytransmitted by continuously depressing the corresponding key.

If it is determined in the step S1810 that the repeat stop signal andthe “ACK” signal have been simultaneously returned, a determination asto whether the key has ceased to be depressed or not is made (stepS1811), and if the key has not ceased to be depressed, the determinationis continuously made.

On the other hand, if the key has ceased to be depressed, whether thecount value of the second timer has become equal to a predeterminedvalue or not is determined so as to determine whether the key has ceasedto be depressed for the predetermined period of time or not, i.e.whether the key has surely ceased to be depressed or not (step S1812).If the count value of the second timer has not become equal to thepredetermined value, the count value of the second timer is incrementedby one (step S1813), and the process returns to the step S1811. On theother hand, if the count value of the second timer has become equal tothe predetermined value, it is determined that the key has surely ceasedto be depressed, and the process returns to the step S1801.

As a result, in the case where a repeat stop signal as well as an “ACK”signal has been received in response to a single-frame control signal,even if a key corresponding to a control signal unsuitable for repeatedcontrol is thereafter continuously depressed, repeated transmission ofthe control signal corresponding to the key is not carried out.

If it is determined in the step S1803 according to the key input that itis determined that the control signal to be transmitted is not asingle-frame control signal, a light signal of one frame is transmittedwhose communication type (“505” in FIG. 5) and packet number (“506” inFIG. 5) have been changed to codes corresponding to multi frames asdescribed above (step S1814).

Next, it is determined whether or not an “ACK” signal has been returnedfrom the controlled apparatus 50 (step S1815). If the “ACK” signal hasnot been returned, the process returns to the step S1814 wherein a lightsignal of the same frame is transmitted again. Namely, in the case ofmulti frames, if an “ACK” signal has not been returned, the same lightsignal is transmitted again without determining whether or not the keyis being continuously depressed.

On the other hand, if the “ACK” signal has been returned, it isdetermined whether all the frames have been transmitted or not (stepS1816). If all the frames have not yet been transmitted, thecommunication type (505) and the packet number (506) are updated (stepS1817), and the process returns to the step S1814 wherein a light signalwith the next frame data is transmitted. If all the frames have beentransmitted, the count value of the second timer is reset (step S1818),and the process proceeds to the step S1811.

As described above, according to the present embodiment, repeatedtransmission inhibition control is not provided for a control signalwith multi frames during key depression. This is because although ittakes a relatively long period of time to completely transmit multiframes, the period of time required for transmission is only a littleshorter than the ON time of a key switch during one key operation, andhence power cannot be saved effectively even if repeated transmission isnot carried out.

However, even in the case of multi frames, if they can be transmittedwithin a short period of time, repeated transmission inhibition controlmay be provided during key depression as is the case with a singleframe.

Next, a description will be given of a sixth embodiment of the presentinvention,

In the above described fourth and fifth embodiments, the controlledapparatus 50 determines whether to inhibit repeated transmission andgives an instruction for inhibiting repeated transmission, but in thesixth embodiment, the remote controller 1 itself determines whether toinhibit repeated transmission and inhibits repeated transmission.

A description will now be given of a control signal transmitting processaccording to the sixth embodiment with reference to a flow chart of FIG.20.

As shown in FIG. 20, in a step S2001, display processing is carried out,in which data to be displayed is selected from data in the data memory 6appearing in FIG. 3 and is displayed. Next, it is determined whetherthere has been a key input or not (step S2002), and if there has been nokey input, the process returns to the step S2001, so that the stepsS2001 and S2002 are executed again.

If there has been a key input, the process proceeds to a step S2003wherein a light signal as a control signal corresponding to the keyinput is transmitted, and the count values of the first timer and thesecond timer provided on the data memory 6 are reset. The first leadercode in FIG. 12A is used as a leader code for the light signaltransmitted in the step S2003 since it is transmitted for the firsttime.

Then, it is determined whether or not an “ACK” signal has been returnedfrom the controlled apparatus 50 (step S2004). If the “ACK” signal hasnot been returned, it is determined whether or not the corresponding keyis being continuously depressed (step S2005). If the key is notcontinuously depressed, the process proceeds to a step S2010, describedlater.

On the other hand, if the key is being continuously depressed, whether apredetermined period of time has elapsed or not is determined by makinga determination as to whether the count value of the first timer hasbecome equal to a predetermined value or not (step S2006). If thepredetermined period of time has not elapsed, the count value of thefirst timer is incremented by one (step S2007), and the process returnsto the step S2004.

On the other hand, if the predetermined period of time has elapsed, alight signal corresponding to the input key is transmitted, and thecounter value of the first timer is reset (step S2008). The process thenreturns to the step S2004. The second leader code in FIG. 12B is used asa leader code for the light signal transmitted in the step S2008 sinceit is transmitted for the second or subsequent time.

If it is determined in the step S2004 that the “ACK” signal has beenreturned, it is determined whether the key corresponds to a controlsignal suitable for repeated control or not (step S2009). It should benoted that keys corresponding to control signals suitable for repeatedcontrol include a key for controlling the volume, and keys for changingthe viewing direction/magnification (zoom) of a monitor camera, and keyscorresponding to control signals unsuitable for repeated control includenumerical keys, and keys for selectively turning on/off specificfunctions.

If it is determined in the step S2009 that the key corresponds to acontrol signal suitable for repeated control, the process proceeds tothe step S2005. Thus, if the key is thereafter continuously depressed,the same light signal as the one transmitted in the step S2003 iscontinuously transmitted at predetermined intervals clocked by the fisttimer until the “ACK” signal is returned. Therefore, even if the lightsignal is temporarily blocked by an obstacle or the like, the lightsignal can be surely received by the controlled apparatus 50 when theobstacle or the like is removed.

If it is determined in the step S2009 that the key corresponds to acontrol signal unsuitable for repeated control, it is then determinedwhether the key has been released or not (step S2010). If the key hasnot been released, the determination is continuously made.

On the other hand, if it is determined that the key has been released, adetermination as to whether the count value of the second timer hasbecome equal to a predetermined value or not is made so as to determinewhether the key has been released for a predetermined period of time ornot, i.e. whether the key has surely ceased to be depressed or not (stepS2011). If the count value of the second timer has not become equal tothe predetermined value, the count value of the second timer isincremented by one (step S2012), and the process returns to the stepS2010. On the other hand, if the count value of the second timer hasbecome equal to the predetermined value, it is determined the key hassurely ceased to be depressed, and the process returns to the stepS2001.

As described above, according to the present embodiment, the sameresults as those of the above described fifth embodiment can beobtained. Further, repeat transmission inhibition can be carried outirrespective of the specifications of the controlled apparatus 50.

According to the above described embodiments of the present invention,even if a key corresponding to a control signal unsuitable for repeatedcontrol is continuously depressed, repeated transmission of the controlsignal corresponding to the key is inhibited to save power for theremote controller 1. Further, due to the elimination of unnecessaryinfrared emission, the period of time for which no infrared is emittedis increased, and hence even if another apparatus to be controlled byinfrared is located in the vicinity of the controlled apparatus 50, itis possible to prevent an infrared communication conflict and prevente.g. malfunction of the apparatuses to be controlled.

It is to be understood that the object of the present invention may alsobe accomplished by supplying a system or an apparatus with a storagemedium (or a recording medium) in which a program code of software whichrealizes the functions of any of the above described embodiments isstored, and causing a computer (or CPU or MPU) of the system orapparatus to read out and execute the program code stored in the storagemedium.

In this case, the program code itself read from the storage mediumrealizes the functions of any of the above described embodiments, andhence the program code and a storage medium on which the program code isstored constitute the present invention.

Further, it is to be understood that the functions of any of the abovedescribed embodiments may be accomplished not only by executing theprogram code read out by a computer, but also by causing an OS(operating system) or the like which operates on the computer to performa part or all of the actual operations based on instructions of theprogram code.

Further, it is to be understood that the functions of any of the abovedescribed embodiments may be accomplished by writing the program coderead out from the storage medium into a memory provided in an expansionboard inserted into a computer or a memory provided in an expansion unitconnected to the computer and then causing a CPU or the like provided inthe expansion board or the expansion unit to perform a part or all ofthe actual operations based on instructions of the program code.

Further, the program code may be implemented by an object code, aprogram which is executed by an interpreter, script data which issupplied to an OS, and so forth insofar as the functions of any of theabove described embodiments can be realized by a computer.

Examples of the storage medium for supplying the program code include aRAM, an NV-RAM, a floppy (registered trademark) disk, an optical disk, amagnetic-optical disk, a CD-ROM an MO, a CD-R, a CD-RW, a DVD-ROM, aDVD-RAM, a DVD-RW, a DVD+RW, a magnetic tape, a nonvolatile memory card,and a ROM, which can store the program code. Alternatively, the programcode may be downloaded from another computer or a database, not shown,connected to the Internet, a commercial network, or a local areanetwork.

1. A remote control system comprising: a remote control apparatus; and a first apparatus controlled by said remote control apparatus; wherein said remote control apparatus comprises: at least one key switch for remote control; and a first transmitting device that repeatedly transmits a control signal corresponding to said key switch while said key switch is being operated and that inhibits the transmission of the control signal in accordance with reception of a predetermined signal from said first apparatus.
 2. A remote control system according to claim 1, wherein said remote control apparatus and said first apparatus communicate with each other by means of infrared light.
 3. A remote control system according to claim 1, wherein said first apparatus comprises: a first determination device that determines whether the control signal, transmitted by said first transmitting device, is suitable for repeated control; and a second transmitting device that transmits an inhibition instruction signal for inhibiting said first transmitting device from repeatedly transmitting the control signal in according with a determination by said first determination device.
 4. A remote control system according to claim 3, wherein said first apparatus comprises a second determination device that determines whether the control signal transmitted by said first transmitting device has been normally received; and wherein said second transmitting device transmits the inhibition instruction signal and an acknowledgement signal indicative of normal reception of the control signal when said second determination device determines that the control signal has been normally received, and said first determination device determines that the control signal is unsuitable for repeated control.
 5. A remote control system according to claim 1, wherein said remote control apparatus comprises: a first determination device that determines whether the control signal corresponding to said key switch, transmitted by said first transmitting device, is suitable for repeated control; and a second determination device that determines whether a response to the control signal has been received from said first apparatus; and wherein said first transmission device is operable to inhibit repeated transmission of the control signal when said first determination device determines that the control signal is unsuitable for repeated control, and said second determination device determines that the response has been received.
 6. A remote control apparatus that remotely controls a first apparatus, comprising: at least one key switch for remote control; a transmitting device that repeatedly transmits a control signal corresponding to said key switch while said key switch is being operated; and an inhibition device that inhibits said transmitting device from repeatedly transmitting the control signal in accordance with reception of a predetermined signal from the first apparatus.
 7. An electronic apparatus that is remotely controlled by a remote control apparatus, comprising: a first determination device that determines whether a same control signal repeatedly transmitted by the remote control apparatus is suitable for repeated control; and a transmitting device that transmits an inhibition instruction signal for inhibiting the repeatedly transmission of the control signal in accordance with a determination by said first determination device.
 8. An electronic apparatus according to claim 7, further comprising a second determination device that determines whether the control signal has been normally received; and wherein said transmitting device transmits the inhibition instruction signal and an acknowledgement signal indicative of normal reception of the control signal when said second determination device determines that the control signal has been normally received, and said first determination device determines that the control signal is unsuitable for repeated control.
 9. A remote control method of remotely controlling a first apparatus by a remote control apparatus, comprising: a transmitting step of repeatedly transmitting a control signal corresponding to a key switch for remote control while the key switch is being operated; and an inhibiting step of inhibiting repeated transmission of the control signal in accordance with reception of a predetermined signal from the first apparatus.
 10. A remote control method of remotely controlled by a remote control apparatus, comprising: a first determination step of determining whether a same control signal repeatedly transmitted by the remote control apparatus is suitable for repeated control; and a transmitting step of transmitting an inhibition instruction signal for inhibiting the repeatedly transmission of the control signal in accordance with a determination in said first determination step.
 11. A program for causing a computer to execute a remote control method of remotely controlling a first apparatus by a remote control apparatus, comprising: a transmitting module for repeatedly transmitting a control signal corresponding to a key switch for remote control while the key switch is being operated; and an inhibiting module for inhibiting repeated transmission of the control signal in accordance with reception of a predetermined signal from the first apparatus.
 12. A program for causing a computer to execute a remote control method of remotely controlled by a remote control apparatus, comprising: a first determination module for determining whether a same control signal repeatedly transmitted by the remote control apparatus is suitable for repeated control; and a transmitting module for transmitting an inhibition instruction signal for inhibiting the repeatedly transmission of the control signal in accordance with a determination in said first determination module.
 13. A remote control system comprising: a remote control apparatus; and a first apparatus controlled by said remote control apparatus; wherein said first apparatus comprises: a first determination device that determines whether a control signal has been normally received from said remote control apparatus; and a returning device that returns an acknowledgement signal indicative of normal reception of the control signal when said determination device determines that the control signal has been normally received; and wherein said remote control apparatus comprises: at least one key switch for remote control; a transmitting device that repeatedly transmits a control signal corresponding to said key switch while said key switch is being operated; a second determination device that determines whether the control signal corresponding to said key switch is suitable for repeated control when the acknowledgement signal is returned from the apparatus to be controlled; and an inhibition device that inhibits said transmitting device from repeatedly transmitting the control signal when said second determination device determines that the control signal corresponding to said key switch is unsuitable for repeated control.
 14. A remote control apparatus that remotely controls a first apparatus; comprising: at least one key switch for remote control; a transmitting device that repeatedly transmits a control signal corresponding to said key switch while said key switch is being operated; a determination device that determines whether the control signal is suitable for repeated control when an acknowledgement signal indicative of normal reception of the control signal is returned from the apparatus to be controlled in response to the control signal; and an inhibition device that inhibits said transmitting device from repeatedly transmitting the control signal when said determination device determines that the control signal is unsuitable for repeated control.
 15. A remote control method of remotely controlling a first apparatus by a remote control apparatus, comprising: a transmitting step of repeatedly transmitting a control signal corresponding to a key switch for remote control while the key switch is being operated; a determination step of determining whether the control signal is suitable for repeated control when an acknowledgement signal indicative of normal reception of the control signal is returned from the apparatus to be controlled in response to the control signal; and an inhibiting step of inhibiting repeated transmission of the control signal when it is determined in said determination step that the control signal is unsuitable for repeated control.
 16. A program for causing a computer to execute a remote control method of remotely controlling a first apparatus by a remote control apparatus, comprising: a transmitting module for repeatedly transmitting a control signal corresponding to a key switch for remote control while the key switch is being operated; a determination module for determining whether the control signal is suitable for repeated control when an acknowledgement signal indicative of normal reception of the control signal is returned from the apparatus to be controlled in response to the control signal; and an inhibiting module for inhibiting repeated transmission of the control signal when it is determined by said determination module that the control signal is unsuitable for repeated control.
 17. A remote control system comprising: a remote control apparatus; and a first apparatus to be controlled by said remote control apparatus; wherein said remote control apparatus comprises: at least one key switch for remote control; and a transmitting device that repeatedly transmits a control signal corresponding to said key switch while said key switch is being operated; wherein said transmitting device adds a discrimination information for discriminating the control signal transmitted for a first time by said transmitting device, and the control signal transmitted for a second or subsequent time by said transmitting device, to the control signal.
 18. A remote control system according to claim 17, wherein said transmitting device transmits the control signal by means of infrared light.
 19. A remote control system according to claim 17, wherein said transmitting device adds a packet number as the discrimination information.
 20. A remote control system according to claim 19, wherein said transmitting device adds a predetermined packet number as the discrimination information to the control signal transmitted for the first time, and cyclically selects and adds one from among a plurality of packet numbers, different from the packet number added to the control signal transmitted for the first time, to the control signal transmitted for the second or subsequent time.
 21. A remote control system according to claim 19, wherein said transmitting device adds a predetermined packet number as the discrimination information to the control signal transmitted for the first time, and adds a predetermined packet number different from the packet number added to the control signal transmitted for the first time, to the control signal transmitted for the second or subsequent time.
 22. A remote control system according to claim 17, wherein said transmitting device adds a predetermined leader code as the discrimination information to a leading end of the control signal transmitted for the first time, and adds a predetermined leader code different from the leader code added to the control signal transmitted for the first time, to a leading end of the control signal transmitted for the second or subsequent time.
 23. A remote control system according to claim 17, wherein said transmitting device adds a predetermined end code as the discrimination information to a trailing end of the control signal transmitted for the first time, and adds a predetermined end code different from the end code added to the control signal transmitted for the first time, to a trailing end of the control signal transmitted for the second or subsequent time.
 24. A remote control apparatus that wirelessly and remotely controls a first apparatus, comprising: at least one key switch for remote control; and a transmitting device that repeatedly transmits a control signal corresponding to said key switch while said key switch is being operated; wherein said transmitting device adds a discrimination information for discriminating the control signal transmitted for a first time by said transmitting device, and the control signal transmitted for a second or subsequent time by said transmitting device, to the control signal.
 25. A remote control method of wirelessly and remotely controlling a first apparatus, comprising: a transmitting step of repeatedly transmitting a control signal corresponding to a key switch for remote control while the key switch is being operated; and an addition step of adding a discrimination information for discriminating the control signal transmitted for a first time and the control signal transmitted for a second or subsequent time to the control signal.
 26. A program for causing a computer to execute a remote control method of wirelessly and remotely controlling a first apparatus, comprising: a transmitting module for repeatedly transmitting a control signal corresponding to a key switch for remote control while the key switch is being operated; and an addition module for adding a discrimination information for discriminating the control signal transmitted for a first time and the control signal transmitted for a second or subsequent time to the control signal. 